DETERMINATION OF THE NUMBER OF CROSS-LINKS IN COLLAGENS FROM MECHANICAL-PROPERTIES OF SWOLLEN FIBERS

A method for the determination of crosslink density for collagen fiber s was proposed. The number of interchain crosslinkages in whale ligame nt and rat-tail tendon was estimated by applying an usual rubber elast icity theory. Collagen fibers swollen in a solution composed of equal volumes of 8M LiBr aqueous solution and diethylene glycol monoalkyl et her showed a typical rubber elasticity. The energy components to total retractive forces were similar in order in magnitude for crosslinked natural rubbers, namely, below 0.3. It was found that no intermolecula r crosslinkage occurs between tropocollagen molecules in tendon from a 2-month-old rat, while there are about 12 crosslinking sites per mole cule in tendon from a 10-month-old rat and 15 sites in whale ligament. The number, type, and crosslinking sites in the tendon crosslinked wi th 1,3-bis(vinylsulfonyl)-2-propanol is also discussed. (C) 1996 John Wiley & Sons, Inc.